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ePWM force to stop output

Felix Zhang
Intellectual 645 points

Hi,

I'm using ePWM1A/1B to output two chanels of PWMs, 1A and 1B are synchronized, set with a Deadband.

Is there any method that I can stop PWM1B output and keep 1A outputting by s/w forece? and at suitable timepoint can let 1B work again?

I read the TZ spec but I think it needs external signals, I'd like noly s/w trigger to stop it / re-work.

Regards,

Felix

  • 0
    TI__Guru 64500 points

    This might be possible by using the Action Qualifier (AQ) submodule of the ePWM.  When software determines that PWM1B should not doing anything, it could modify the action for channel B to "do nothing".  And then when software determines it should turn back on, setup the appropriate action at that time.

    This is just my initial thoughts.  I haven't verified this.

  • 0 in reply to BrandonAzbell
    Intellectual 645 points

    Brandon,

    Thanks, I tried another way that setup the 1B pin as GPIO and set High output, it seems working now but I'd like confirm if this is reliable, thanks a lot!

    Regards,

    Felix

  • 0 in reply to Felix Zhang
    TI__Genius 10820 points

    Hi Felix,

    I believe using the action qualifier method is the best way to solve this issue. However, in this case you should not use the dead-band sub-module of the PWM. Instead you will need to generate PWM1A and 1B outputs using the action qualifier. You could then force PWM1B low using the action qualifier settings.

    The action qualifier method allows you to force the output low/high at a known good point of the PWM cycle (example: at the end of the current period). Configuring the 1B output as GPIO and setting it high will work, but the action may take effect at anytime in the current PWM cycle. If this is acceptable for the powerstage/load that your PWMs are driving, this should be OK.

    Hrishi

  • 0 in reply to Hrishi Nene
    Intellectual 645 points

    Hi Hrishi,

    Thanks a lot!

    Regards,

    Felix